1. Field of the Invention
The present invention relates to a light emitting device and a method of manufacturing the same, and more particularly, to a light emitting diode (LED) having a high emission efficiency, capable of operating at a low voltage and emitting blue and green lights, and a method of manufacturing the same.
2. Description of the Related Art
LEDs are widely used as a light source of an optical communication apparatus and a light source to visually display the operating state of an electronic apparatus. Accordingly, a variety of LEDs are provided according to the application fields of devices using LEDs. The range of use of LEDs has more expanded by semiconductor devices emitting a blue light or a green light.
FIG. 1 is an example of a conventional LED.
Referring to FIG. 1, an n-GaN layer 12 is formed on a substrate 10. The n-GaN layer 12 is divided into a first region R1, on which an active layer 14 is formed, and a second region R2, on which an n-type electrode 22 is formed. There is a step between the first and second regions R1 and R2. The active layer 14, a p-GaN layer 16, and a p-type electrode 18 are formed sequentially on the first region R1 of the n-GaN layer 12. Here, the p-type electrode 18, as a high reflective electrode, reflects the light emitted from the active layer 14 toward the substrate 10.
Due to the high contacting resistance between the p-GaN layer 16 and the p-type electrode 18 in the conventional LED, the emission efficiency is low at a predetermined voltage. The problem of low emission efficiency could be solved by increasing the operating voltage.
However, attempts to solve the low emission efficiency problem of the LED by simply applying a higher operating voltage to the p-type electrode 18, and maintaining the high contact resistance between the p-GaN layer 16 and the p-type electrode 18 run against the efforts to reduce the operating voltage. This can cause a new problem.